The present invention relates to an image forming apparatus.
A general image forming apparatus such as a printer (for example, a color printer), a copier, a facsimile machine, a combined machine or the like includes a sheet feeder portion provided inside or outside of a main body of the image forming apparatus. Sheets (i.e., media) are set in the sheet feeder portion. In the case where a plurality of sheets (i.e., a stack) are set in the sheet feeder portion, a topmost sheet is separated from other sheets by a separation mechanism, and is transported by a transport mechanism to an image forming portion in the main body of the image forming apparatus.
The conventional sheet feeder portion includes a separation mechanism with a separation pad. In such a conventional sheet feeder portion, a sheet placing plate is biased in a direction toward a feed roller so that the topmost sheet of the stack on the sheet placing plate contacts the feed roller. The feed roller brings the topmost sheet to a portion between the feed roller and the separation pad composed of a friction piece. Due to a friction between the sheet and the separation pad, the sheet is separated, and is fed in a predetermined direction. The feed roller is mounted to a roller shaft, and a rotation of a drive motor is transmitted to the feed roller via the roller shaft.
Further, a pair of guide rollers are fixed to the roller shaft on both sides of the feed roller (to be more specific, on symmetrical positions with respect to the feed roller). The guide rollers rotate together with the roller shaft, and guide the sheet at the vicinities of widthwise edges of the sheet (see, for example, Patent Document No. 1).
Patent Document No. 1: Japanese Laid-Open Patent Publication No. 2007-099416
However, in the above described sheet feeder portion, when the guide rollers guide the sheet, the sheet may be partially bent by being pressed against the guide rollers, and a reaction force may be caused by the bending of the sheet. As a result, a friction may occur between the sheet currently being fed and the next sheet, and a friction may occur between the sheet currently being fed and the feed roller. That is, a feed load (i.e., a load applied to the feed roller for feeding the sheets) may be generated.